In a known rotary operating device including a rotary knob, a required candidate is selected from list elements by operating the rotary knob, and then the candidate is fixed by pressing a switch or the like.
For example, an electronic operating device including a rotary encoder or the like in a rotation-operating mechanism is provided with a rotary operation knob so that an operator can select a required candidate by detecting the amount (angle) of the rotation of the operation knob.
However, in the conventional operating device, the rotary operation knob is formed of components having the same diameter; hence, the operating device is not user friendly in view of the operation speed and accuracy.
For example, with recent development of large-capacity recording media such as hard disks and data compression technology (such as MP3), it is nothing special that one medium can record an enormous amount of data. In such a circumstance, the file structure for handling folders and albums in the recording field in the same media is layered and the depth of the hierarchy increases. In one method for achieving a desired selection processing by a high-speed operation under such a condition, a rotary knob dedicated for a high-speed operation and a fine rotary knob dedicated for a low-speed operation and fine adjustment are provided. After the rotary knob for high-speed operation is rotated, the fine rotary knob for low-speed operation is rotated for retrieving and selecting a desired file or the like.
In such a method, however, an operator must use these two rotary knobs to suit the occasion with trouble, and cannot visually select the knob to be rotated in a minute.
Accordingly, an object of the present invention is to strike a balance between high-speed operation and accuracy in an operating device capable of a rotation operation by a rotary knob and is to avoid the necessity of the use of a plurality of rotary knobs.